Hitherto, there has only been a small number of technically viable phosphors which can be excited in the UV and in particular in the blue spectral region and emit in the blue to orange-yellow (dominant wavelength 450 to 590 nm). In particular, stable green phosphors with an emission maximum from 525 to 530 nm are scarcely available. This makes it difficult to use luminescence conversion LEDs for display backlighting and restricts the optimization of LED with high color rendering or low luminous color, such as warm-white. Hitherto, primarily standard orthosilicates have been used as green phosphor for these applications in products of this type. However, they can only be moderately excited in particular in the blue. Although the emission can be optimized by mixing the cations Ba, Sr, Ca, one such example being SrCaSiO4:Eu, this mixture often leads to a deterioration in the quantum efficiency, in this case compared to pure Sr2SiO4:Eu.
An othosilicate of this type is known for example from WO 03/080763, which is (Ba, Sr, Ca)SiO4:Eu which emits in the green at approximately 530 nm. It is used together with further phosphors.